An integrated circuit (IC) die is often fabricated into a processor for various tasks. IC operation invariably leads to heat generation and thermal expansion stresses in a die package. High melting point solder, although they withstand the high operating temperatures caused by the densely packed circuitry in a die, requires high processing temperature, which can cause high thermal-mechanical stress due to coefficient of thermal expansion (CTE) mismatch between semiconductive die and organic substrate. But for low melting solder, the electro-migration is much more easily to happen. Additionally, corrosion can occur between the two disparate metals of the solder bump and the bond pad.